Stabilized recycled plastics

ABSTRACT

The invention relates to stabilized recycled plastics, which can be obtained from domestic, commercial and industrial waste or valuable material collections, comprising a macrocyclic compounds containing a radical of formula (I) or (II), in the macrocycle or in a side group of the macrocycle, where the macrocycle comprises at least 8 atoms and in which the substituents R, independently of one another, are methyl, ethyl or propyl, or two radicals R on the same carbon atom are, together, a pentamethylene radical, and a is the number 0, 1 or 2. The invention also relates to a process for the stabilization of recycled plastics and to the use of the above macrocyclic compounds as stabilizer. ##STR1##

The invention relates to stabilized recycled plastics, as predominantlyproduced in the household, in commerce and also in industry and invaluable material collections, and to a stabilization process and to theuse of a stabilizer.

The recycling of waste is a task of increasing importance for ecologicalreasons. The recycling of paper, textiles, glass or metals is alreadycarried out on a large scale, whether by separate collection or bysorting of the refuse. The recycling of plastic waste and used plasticsis also an increasing aim. Thermoplastics are generally processed byre-melting.

The plastic waste produced in the household, in commerce or in industryor the valuable plastic materials or used plastics obtained fromcollections or a return obligation, for example in specific sectors ofindustry, such as the automobile industry, electrical industry,agriculture or the packaging industry, predominantly comprisesthermoplastics based on polyolefins, styrene polymers, polyvinylchloride or polyesters.

These used plastics, which may constitute valuable raw materials, can beobtained either as a single type or as a mixture. Single-type plasticwaste can be generated directly during production of plastic parts orobtained by separate collections or sorting.

On the other hand, the recycling of used plastic frequently means theuse of a mixture of different types of plastic. Known industrialseparation methods, for example hydrocyclone separation, mostly giveonly moderately clean fractions of various plastic mixtures, for examplea polyolefin mixture.

The post-stabilization of recycled plastics is disclosed, for example,in WO 94/07946, WO 94/07950 and WO 94/07951. The main proposal here isto use compounds from the group consisting of the phosphites and/orsterically hindered phenols.

For the stabilization of recycled high-density polyethylene, P. Vink, R.T. Rotteveel and J. D. M. Wisse in Polymer Degr. and Stability, Issue 9,p.133 (1984) studied various stabilizers from the classes of thephosphites, hindered phenols, benzotriazoles, hindered amines andphosphonites.

These authors also indicated that the recyclates must be re-stabilized.Although the plastics have mostly been treated originally withstabilizers against thermooxidative and in some cases also againstphotooxidative degradation, these stabilizers are lost during use of theplastics, during storage of the waste and during processing of therecyclates, in some cases due to migration, extraction or bydegradation. In addition, a recycled plastic generally differsstructurally and also chemically from a new plastic as a consequence ofthe prior use or due to storage and processing; for example, initiatorpoints (hydroperoxides, carbonyl groups etc.) for oxidative attack mayalready have formed due to oxidation. An additional adverse effect onthe ageing behaviour can be due to foreign substances, for example paperor adhesives. These foreign substances can also originate from contactwith diverse substances during use or processing, for example paintcomponents, printing inks, wood, traces of metal, initiator residues ortraces of water. A recycled plastic therefore requires, for example, arelatively large amount of stabilizers or alternatively stabilizerswhich take into account these particular circumstances. The difficultyof finding suitable stabilizers is due to the specific type of previousdamage/impurities, which may have taken place over an extended period.

The stabilization of a plastic mixture is also a difficult task, sinceeach type of plastic makes specific requirements of the stabilizers.Thus, for example, completely different stabilizers are used for vinylchloride polymers than for polyolefins or styrene polymers.

Owing to previous damage and impurities, recyclates also have a modifiedsolution behaviour vis-a-vis additives. For example, an increase in theconcentration of polar additives through dissolution in polar componentscan be expected, which adversely affects the ageing stability as a wholeand means that a complex additive mixture would be required for goodrecyclate stability.

It would therefore be necessary to add a mixture of various stabilizersin order to stabilize a plastic mixture. In the case of complex plasticmixtures, this is a complicated method.

Worthwhile recycling is also possible, in particular, if the recyclatescan be used in relatively high-quality applications. Examples ofrelatively high-quality applications are those which are intended towithstand outside use for a long period (such as refuse containers,pallets, garden furniture, pipes, containers, automobile parts, housingparts, etc.).

It is therefore a particular object of the present invention to providea stabilized recycled plastic which has improved long-term behaviour andimproved weathering properties. The additive used for this purposeshould have the simplest possible composition and should be universallyusable without slight variations, as are usual in recyclates fromcollections, requiring a modification of the stabilization, as caneasily be necessary when a complex mixture is used.

It has now been found that both single-type and mixed recycled plasticscan, in the presence of certain macrocyclic compounds containingpiperidinyl or piperazinyl groups, be stabilized simply and economicallyagainst thermal, oxidative and/or actinic degradation during processingand subsequent use.

The invention thus relates to stabilized recycled plastics, which can beobtained from domestic, commercial and industrial waste or valuablematerial collections, comprising from 0.01 to 5% by weight, based on theplastic, of at least one macrocyclic compound containing a radical ofthe formula ##STR2## in the macrocycle or in a side group of themacrocycle, where the macrocycle comprises at least 8 atoms and in whichthe substituents R, independently of one another, are methyl, ethyl orpropyl, preferably methyl, or two radicals R on the same carbon atomare, together, a pentamethylene radical, and a is the number 0, 1 or 2,preferably 0.

Preference is given to macrocyclic compounds in which the macrocyclecomprises at least 9 atoms and very particular preference is given tothose comprising from 9 to 50 atoms in the macrocycle.

From 0.05 to 2% by weight, in particular from 0.1 to 1% by weight, basedon the plastic, of the above macrocyclic compound is preferably used.

The recycled plastics are predominantly thermoplastic polymers ormixtures/blends. Examples of predominantly thermoplastic polymers ormixtures/blends are those whose thermoplastic content is greater than95% by weight, preferably greater than 97% by weight.

The plastics to be stabilized are, for example, used plastics fromhouseholds and commerce (for example supermarkets), which predominantlyoriginate from packaging materials. These can be, for example, films,bags, bottles and other containers or foams. Other materials may also bepresent. However, it is also possible for the above-describedsingle-type plastics which have been previously damaged by use, storageor processing to be stabilized. The materials originate, for example,from separation/sorting or from specific areas of industry or returnobligations, for example from the automobile industry,electrical/electronic industry, construction, agriculture and thetextile industry.

Single-type plastics which have been previously damaged duringprocessing are, for example, those produced on conversion of a plasticpowder or granular commercial product into an end product. A recyclatecan also be formed from production waste, for example the sprues, edgetrimmings and faulty batches.

The invention relates to single-type, recycled plastics, for examplefrom the polymer classes consisting of the polyolefins, polystyrenes andpolyesters, to defined recycled mixtures, known as polymer blends, orcopolymers, for example ABS, SIS, SEBS, PE/PP, PET/PC, PBT/PC orPP/EPDM, but also to recycled plastic mixtures.

These recycled plastic mixtures comprise predominantly thermoplastics,for example polyolefins, polystyrene, polyvinyl chloride and engineeringplastics such as polyamides, polycarbonates and polyesters. The recycledplastic mixtures mainly comprise 25-100% by weight, in particular35-100% by weight, of polyolefins, 0-25% by weight of polystyrene, 0-25%by weight of polyvinyl chloride and 0-25% by weight of otherthermoplastics, it also being possible for mixtures to be present withinthese groups of thermoplastics. Non-thermoplastics may also be presentin the mixture in small amounts, e.g. less than 5% by weight.

In particular, the invention relates to recycled plastic mixtures whichcomprise 55-100% by weight of polyolefins, 0-25% by weight ofpolystyrene, 0-15% by weight of polyvinyl chloride and 0-10% by weightof other thermoplastics.

A polyolefin mixture comprises, for example, HDPE, PP and/or LDPE and/orLLDPE.

In the case of single-type recyclates, the invention relates, inparticular, to polyolefins, polystyrenes and polyesters. Particularpreference is given to single-type polyolefin recyclates, for examplepolypropylene, HD polyethylene, LD polyethylene and polypropylene blendsand copolymers, for example PP/EPDM and PP/PE.

The invention furthermore relates to stabilized polyolefin mixturescomprising virtually exclusively polyolefins having differentstructures.

In plastic mixtures, the dominant polyolefins are usually polyethylene(PE) and polypropylene (PP), in particular low-density polyethylene(LDPE), linear low-density polyethylene (LLDPE) and high-densitypolyethylene (HDPE), furthermore copolymers such as ethylene-propylene(EPM) and ethylene-propylene-diene (EPDM) copolymers and ULDPE and MDPE.Polystyrene (PS and EPS) is also taken to mean copolymers containingstyrene (for example ABS, ASA, HIPS, IPS and SIS), and polyvinylchloride (PVC) is also taken to mean copolymers predominantly comprisingvinyl chloride (for example CPE). Of other thermoplastics, valuablematerial collections principally contain polyethylene terephthalate(PET), and in addition polyamides, polycarbonate, cellulose acetate andpolyvinylidene chloride. Secondary amounts, up to about 5%, ofnon-thermoplastics, for example polyurethanes, formaldehyde resins andphenolic resins, and typical amino resins, and also elastomers, forexample vulcanized or unvulcanized rubber, may also be present. Incertain plastic wastes, small amounts of foreign substances, for examplepaper, pigments and adhesives, which are frequently difficult to remove,may also be present. These foreign substances may also originate fromcontact with diverse substances during use or processing, for examplefuel residues, paint components, traces of metal, printing inks,initiator residues or traces of water.

Preferred macrocyclic compounds containing piperidinyl or piperazinylgroups are macrocyclic compounds of the formulae (III) to (VI) below,particular preference being given to those of the formulae (IV) and (V):##STR3## where L₁ is the radical ##STR4## and A₁ is >CH-- or nitrogen ora substituted carbon atom (*C) of the formula ##STR5## A₂ is C₁ -C₁₂alkylene, C₄ -C₁₂ alkenylene, xylylene, a divalent radical of analiphatic, cycloaliphatic, araliphatic or aromatic dicarboxylic acid,dicarbamic acid or phosphorus-containing acid or a divalent silylradical, preferably a radical of an aliphatic dicarboxylic acid having 2to 36 carbon atoms, of a cycloaliphatic or aromatic dicarboxylic acidhaving 8 to 14 carbon atoms or of an aliphatic, cycloaliphatic oraromatic dicarbamic acid having 8 to 14 carbon atoms;

A₃ and A₄, independently of one another, are C₁ -C₁₂ alkylene, C₂ -C₁₂alkylene which is interrupted by oxygen, sulfur or NR₄, C₄ -C₁₂alkenylene, xylylene or a divalent triazinyl radical of the formula##STR6## preferably C₁ -C₁₂ alkylene, C₂ -C₁₂ alkylene which isinterrupted by oxygen, sulfur or NR₄, or a divalent triazinyl radical ofthe formula ##STR7## A₅ is a radical of the formula ##STR8## A₆ is aradical of the formula ##STR9## A₇ is --OR₆, --SR₆ or --NR₄ R₆ ; R,independently of one another, are methyl, ethyl or propyl, or tworadicals R on the same carbon atom can together be a pentamethyleneradical, preferably methyl;

R₁ is hydrogen, oxygen, hydroxyl, C₁ -C₁₂ alkyl, C₃ -C₈ alkenyl, C₃ -C₈alkynyl, phenyl-C₁ -C₆ alkyl, C₁ -C₁₈ alkoxy, C₅ -C₈ cycloalkoxy, C₇ -C₉phenylalkoxy, C₁ -C₈ alkanoyl, C₃ -C₅ akenoyl, C₁ -C₁₈ alkanoyloxy,benzoxy, glycidyl or a --CH₂ CH(OH)--R₃ group, preferably hydrogen, C₁-C₄ alkyl, allyl, benzyl, acetyl or acryloyl;

R₂, independently of one another, are hydrogen or C₁ -C₁₂ alkyl;

R₃ is hydrogen, methyl or phenyl;

R₄ is hydrogen, C₁ -C₁₂ alkyl or, together with R₆, is --(CH₂)₂--O--(CH₂)₂ --;

R₅ is C₁ -C₁₈ alkyl;

R₆ is hydrogen, C₁ -C₁₈ alkyl, ω-hydroxy-C₁ -C₁₈ alkyl, ω-C₁ -C₁₈alkoxy-C₁ -C₁₈ allyl, C₃ -C₁₈ alkenyl, C₅ -C₁₈ cycloalkyl, substitutedor unsubstituted phenyl, substituted or unsubstituted phenyl-C₁ -C₆alkyl, --CH₂ --C(═O)--O--R₅ or, together with R₄, --(CH₂)₂ --O--(CH₂)₂--, preferably C₁ -C₁₂ alkyl, C₃ -C₁₂ alkenyl, C₅ -C₁₂ cycloalkyl,phenyl, phenyl-C₁ -C₄ alkyl, --CH₂ --C(═O)--O--R₅ or, together with R₄,--(CH₂)₂ --O--(CH₂)₂ --;

a is the number 0, 1 or 2, preferably 0;

m is the number 1, 2 or 3, preferably 1;

n₁, n₂ and n₃, independently of one another, are a number from 1 to 12,preferably 2, 3, 4 or 6; and

t₁, t₂, t₃ and t₄, independently of one another, are a number from 1 to12, preferably a number from 1 to 6.

Suitable alkyl substituents with up to 18 carbon atoms in the aboveformulae are radicals such as methyl, ethyl, propyl, butyl, pentyl,hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tetradecyl,hexadecyl and octadecyl, and the corresponding branched isomers.

Suitable cycloalkyl substituents with up to 18 carbon atoms in the aboveformulae are radicals such as cyclohexyl, cyclooctyl, cycloundecyl andcyclododecyl.

Suitable ω-hydroxy-alkyl substituents with up to 18 carbon atoms in theabove formulae are radicals such as 2-hydroxyethyl, 3-hydroxypropyl,4-hydroxybutyl and radicals analogous to the above alkyl radicals.

Suitable ω-alkoxyalkyl substituents with up to 36 carbon atoms in theabove formulae are radicals such as 2-ethoxyethyl, 3-ethoxypropyl,4-ethoxybutyl and radicals analogous to the above alkyl radicals.

Suitable alkylene substituents with up to 12 carbon atoms in the aboveformulae are radicals such as ethylene, 1,2- and 1,3-propylene,tetramethylene, pentamethylene, hexamethylene and radicals analogous tothe above alkyl radicals.

Suitable allylene substituents with up to 12 carbon atoms in the aboveformulae which are interrupted by oxygen, sulfur or NR₄ are radicalssuch as --(CH₂)₂ --O--(CH₂)₂ --, --(CH₂)₃ --O--(CH₂)₃ --, -- (CH₂)₂--O--(CH₂)₂ !₂₋₃ --, --(CH₂)₂ --S--(CH₂)₂ --, --(CH₂)₃ --S--(CH₂)₃ --,-- (CH₂)₂ --S--(CH₂)₂ !₂₋₃ --, --(CH₂)₂ --NH--(CH₂)₂ --, --(CH₂)₃--NH--(CH₂)₃ --, -- (CH₂)₂ --NH--(CH₂)₂ !₂₋₃ --, --(CH₂)₂ --N(CH₂CH₃)--(CH₂)₂ --, --(CH₂)₃ --N(CH₂ CH₃)--(CH₂)₃ -- and radicals analogousto the above alkylene radicals.

Suitable alkoxy substituents with up to 18 carbon atoms in the aboveformulae are radicals such as methoxy and ethoxy, and radicals analogousto the above alkyl radicals.

Suitable alkanoyl substituents with up to 8 carbon atoms in the aboveformulae are radicals such as formyl, acetyl, propionyl, butyryl andoctanoyl.

Suitable alkanoyloxy substituents with up to 18 carbon atoms in theabove formulae are radicals such as acetoxy, propionyloxy, butyryloxyand octanoyloxy.

Suitable cycloalkoxy substituents with up to 8 carbon atoms in the aboveformulae are radicals such as cyclohexyloxy and cyclooctyloxy.

Suitable phenylalkoxy substituents with up to 12 carbon atoms in theabove formulae are radicals such as ##STR10##

Suitable alkenyl substituents with up to 18 carbon atoms in the aboveformulae are radicals such as vinyl, prop-1-enyl (--CH═CH--CH₃) orprop-2-enyl (--CH₂ --CH═CH₂), and radicals analogous to the above alkylradicals.

Suitable alkenylene substituents with up to 12 carbon atoms in the aboveformulae are radicals such as 1,2- and 1,3-prop-1-enylene,1,4but-1-enylene, 1,4-but-2-enylene, 1,2-but-3-enylene and radicalsanalogous to the above alkylene radicals.

Suitable alkenoyl substituents with up to 8 carbon atoms in the aboveformulae are radicals such as acryloyl.

Suitable alkynyl substituents with up to 8 carbon atoms in the aboveformulae are radicals such as prop-1-ynyl, prop-2-ynyl, but-1-ynyl,but-2-ynyl and radicals analogous to the above alkenyl radicals.

Suitable phenyl--C₁ -C₆ alkyl substituents in the above formulae areradicals such as ##STR11## Suitable dicarboxylic acid substituents inthe above formulae are radicals such as those of malonic acid, succinicacid, glutaric acid, adipic acid, suberic acid, sebacic acid, maleicacid, itaconic acid, phthalic acid, dibutylmalonic acid, dibenzylmalonicacid, butyl(3,5-di-tert-butyl-4-hydroxybenzyl)malonic acid,bicycloheptenedicarboxylic acid, hexamethylenedicarbamic acid and2,4-tolylenedicarbamic acid.

Substituents on phenyl radicals are taken to mean one to five,preferably one or two, substituents such as C₁ -C₈ alkyl, C₁ -C₈ alkoxyor --OH.

A particularly preferred macrocyclic compound containing piperidinyl orpiperazinyl groups is a macrocyclic compound of the formula ##STR12##where L₁ is the radical ##STR13## and A₇ is --NR₄ R₆ ;

R is methyl;

R₁ is hydrogen, oxygen, hydroxyl, C₁ -C₁₂ alkyl, C₃ -C₈ alkenyl,phenyl-C₁ -C₆ alkyl, C₁ -C₁₈ alkoxy, C₃ -C₅ alkenoyl or C₁ -C₁₈alkanoyloxy, preferably hydrogen, C₁ -C₄ alkyl, allyl, benzyl, acetyl oracryloyl;

R₄ is hydrogen, C₁ -C₁₂ alkyl or, together with R₆, --(CH₂)₂ --O--(CH₂)₂--;

R₅ is C₁ -C₁₈ allyl;

R₆ is C₁ -C₁₈ alkyl, C₃ -C₁₈ alkenyl, C₅ -C₁₈ cycloalkyl, substituted orunsubstituted phenyl, substituted or unsubstituted phenyl-C₁ -C₆ alkyl,--CH₂ --C(═O)--O--R₅ or, together with R₄, --(CH₂)₂ --O--(CH₂)₂ --,preferably C₁ -C₁₂ alkyl, C₃ -C₁₂ alkenyl, C₅ -C₁₂ cycloalkyl, phenyl,phenyl-C₁ -C₄ alkyl, --CH₂ --C(═O)--O--R₅ or, together with R₄, --(CH₂)₂--O--(CH₂)₂ --;

a is the number 0, 1 or 2, preferably 0;

n₄ is a number from 1 to 12, preferably 2, 3, 4 or 6; and

t₃ is a number from 1 to 4, preferably 1 or 2.

The macrocyclic compound containing piperidinyl or piperazinyl groups isvery particularly preferably a macrocyclic compound of the formula(VII), as described above, where R₄ is hydrogen or, together with R₆,--(CH₂)₂ --O--(CH₂)₂ --, R₆ is --C(CH₃)₂ --CH₂ --C(CH₃)₃, cyclohexyl,phenyl, --CH₂ --C(═O)--O--R₅ or, together with R₄, --(CH₂)₂ --O--(CH₂)₂--.

The compounds of the formula VII can, if desired, be in the form of amixture of the monomeric compounds (t₃ =1), dimeric compounds (t₃ =2),trimeric compounds (t₃ =3) and/or tetrameric compounds (t₃ =4).

A compound of the formula VII in which t₃ is 2 can, for example, be inthe form of a mixture with a compound of the formula VII in which t₃ is1 in a ratio of from 10:1 to 1:10.

A preferred embodiment of the invention is a stabilized recycled plasticcomprising from 0.01 to 5% by weight, based on the plastic, of a mixtureof the compounds VII-A and VII-B ##STR14## where L₁ is ##STR15## R is--CH₃, R₁ is H and a is 0, in a ratio (parts by weight) of from 10:1 to1:10, preferably from 10:1 to 1:1 or from 5:1 to 1:1. A particularlypreferred ratio between the compounds (VII-A) and (VII-B) is 7:3.

The above-described macrocyclic compounds are disclosed, for example, inU.S. Pat. No. 4,442,250, U.S. Pat. No. 5,004,759 and EP-A-0 446 171 orcan be obtained by the methods outlined therein.

In accordance with the invention, from 0.01 to 2% by weight of at leastone sterically hindered phenol and/or from 0.01 to 2% by weight of atleast one organic phosphite or phosphonite can additionally be added tothe recycled plastic.

The phenol:ester weight ratio is preferably from 20:1 to 1:20,particularly preferably from 10:1 to 1:10, very particularly preferably4:1 to 1:4.

The sterically hindered phenols are known stabilizers againstthermooxidative ageing of plastics, in particular polyolefins. Thesecompounds preferably contain at least one group of the formula (X)##STR16## in which R' is hydrogen, methyl or tert-butyl, and R" issubstituted or unsubstituted alkyl or substituted alkylthioalkyl.

Examples of sterically hindered phenols of this type are:

2,6-di-tert-butyl-4-methylphenol, 2-tert-butyl-4,6-dimethylphenol,2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-n-butylphenol,2,6-di-tert-butyl-4-i-butylphenol, 2,6-dicyclopentyl-4-methylphenol,2-(α-methylcyclohexyl)-4,6-dimethylphenol,2,6-dioctadecyl-4-methylphenol, 2,4,6-tricyclohexylphenol,2,6-di-tert-butyl-4-methoxymethylphenol, 2,6-dinonyl-4-methylphenol,2,6-di-tert-butyl-4-methoxyphenol, 2,5-di-tert-butylhydroquinone,2,5-di-tert-amylhydroquinone, 2,6-diphenyl-4octadecyloxyphenol,2,2'-thiobis(6-tert-butyl-4-methylphenol), 2,2'-thiobis(4-octylphenol),4,4'-thiobis(6-tert-butyl-3-methylphenol),4,4'-thiobis(6-tert-butyl-2-methylphenol),2,2'-methylenebis(6-tert-butyl-4-methylphenol),2,2'-methylenebis(6-tert-butyl-4-ethylphenol), 2,2'-methylenebis4-methyl-6-(α-methylcyclohexyl)phenol!,2,2'-methylenebis(4-methyl-6-cyclohexylphenol),2,2'-methylenebis(6-nonyl-4-methylphenol),2,2'-methylenebis(4,6-di-tert-butylphenol),2,2'-ethylidenebis(4,6-di-tert-butylphenol),2,2'-ethylidenebis(6-tert-butyl-4-isobutylphenol), 2,2'-methylenebis6-(α-methylbenzyl)-4-nonylphenol!, 2,2'-methylenebis6-(α,α-dimethylbenzyl)-4-nonylphenol!,4,4'-methylenebis(2,6-di-tert-butylphenol),4,4'-methylenebis(6-tert-butyl-2-methylphenol),1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,2,6-bis(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol,1,1,3-tris(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)-3-n-dodecylmercaptobutane,ethylene glycol bis 3,3-bis(3'-tert-butyl-4'-hydroxyphenyl)butyrate!,bis(3-tert-butyl-4-hydroxy-5-methylphenyl)dicyclopentadiene, bis2-(3'-tert-butyl-2'-hydroxy-5'-methylbenzyl)-6-tert-butyl-4-methylphenyl!terephthalate,1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene,bis(3,5-di-tert-butyl-4-hydroxybenzyl)sulfide, isooctyl3,5-di-tert-butyl-4-hydroxybenzylmercaptoacetate,bis(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) dithioterephthalate,1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate,1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl)isocyanurate,dioctadecyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate and the calciumsalt of monoethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate.

Particular preference is given to compounds containing at least onegroup of the formula ##STR17## in which R' is methyl or tert-butyl, andR" is substituted or unsubstituted alkyl or substituted alkylthioalkyl.

Examples of such hindered phenols are the esters ofβ-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid and ofβ-(5-tert-butyl-4-hydroxy-3-methylphenyl)propionic acid with monohydricor polyhydric alcohols, for example with methanol, octanol, octadecanol,1,6-hexanediol, neopentyl glycol, thiodiethylene glycol, diethyleneglycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl)isocyanurate, N,N'-bis(hydroxyethyl)oxalamide, and the amides of theseacids, for exampleN,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexamethylenediamine,N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)trimethylenediamineand N,N'-bis(3,5-di-tert-butyl4-hydroxyphenylpropionyl)hydrazine, andbis(3-tert-butyl-4-hydroxy-5-methylphenyl)dicyclopentadiene andcorresponding oligomers.

Other particularly preferred compounds are: ##STR18##(2-(1,1-dimethylethyl)-6-3-(1,1-dimethylethyl)-2-hydroxy-5-methylphenyl!methyl!-4-methylphenyl2-propenoate), ##STR19## (1,6-hexylene3,5-bis(1,1-dimethylethyl)-4-hydroxybenzenepropionate), ##STR20##(triethylene glycol bis3-(1,1-dimethylethyl)-4-hydroxy-5-methylphenylpropionate!), ##STR21##(2-methyl-4,6-bis (octylthio)methyl!phenol), ##STR22##(2,2'-ethylidenebis(4,6-di-tert-butylphenol); ##STR23## (thiodiglycolbis 3,5-bis(1,1-dimethylethyl)-4-hydroxybenzenepropionate!), ##STR24##(1,3,5-tris2,6-bis(1,1-dimethylethyl)-4-hydroxybenzyl!-2,4,6-trimethylbenzene).##STR25## (1,3,5-tris3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl!methyl!-1,3,5-triazine-2,4,6(1H,3H,5H)trione),

Very particular preference is given to the pentaerythrityl ester, theoctyl ester and the octadecyl ester ofβ-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid,2,2'-ethylidenebis(4,6-di-tert-butylphenol) andbis(3-tert-butyl-4-hydroxy-5-methylphenyl)dicyclopentadiene and thecorresponding oligomers.

The organic phosphites and phosphonites are likewise known asstabilizers for plastics. They are used, in particular, as processingstabilizers for polyolefins.

They are predominantly aromatic phosphites and phosphonites, for exampletriphenyl phosphite, diphenyl alkyl phosphites, phenyl dialkylphosphites, tris(diphenyl alkyl phosphite)amines, tris(nonylphenyl)phosphite, trilauryl phosphite, trioctadecyl phosphite, distearylpentaerythrityl diphosphite, tris(2,4-di-tert-butylphenyl) phosphite,distearyl pentaerythrityl diphosphite, bis(2,4-di-tert-butylphenyl)pentaerythrityl diphosphite, tristearyl sorbityl triphosphite,tetrakis(2,4di-tert-butylphenyl)-4,4'-biphenylene diphosphonite,3,9-bis(2,4-di-tert-butyl-4-methylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro5.5!undecane,3,9-tris(2,4,6-tris-tert-butylphenoxy)-2,4,8,10-tetraoxa-3,9-diphosphaspiro5,5!undecane and 2,2'-ethylidenebis(4,6-di-tert-butylphenyl)fluorophosphite. Particular preference is given to the followingphosphites: tris(2,4-di-tert-butylphenyl)phosphite; ##STR26##

Very particular preference is given to tris(2,4-di-tert-butylphenyl)phosphite.

Also expedient are plastic compositions as described above whichadditionally comprise a metal soap, for example an organozinc,organomagnesium or organocalcium compound from the series consisting ofaliphatic saturated C₁ -C₂₂ carboxylates, aliphatic olefinic C₂ -C₂₂carboxylates, aliphatic C₂ -C₂₂ carboxylates which are substituted by atleast one OH group, cyclic and bicyclic carboxylates having 5-22 carbonatoms, aromatic C₆ -C₂₂ carboxylates, aromatic C₆ -C₂₂ carboxylateswhich are substituted by at least one OH group, C₁ -C₁₆alkyl-substituted phenylcarboxylates, phenyl--C₁ -C₁₆ alkylcarboxylates,C₆ -C₁₈ phenoxides, C₅ -C₂₆ chelates of 1,3-diketones orβ-ketocarboxylates, dehydraacetic acid and derivatives thereof,mercaptides based on mercaptocarboxylates, and glycinates.

Also expedient are plastic compositions as described above whichadditionally comprise an inorganic compound from the series consistingof metal oxides, metal hydroxides and metal carbonates.

These are, in particular, metal oxides, metal hydroxides and metalcarbonates of elements from main group I or sub-group II, IV or VII.Preference is furthermore given to calcium, magnesium, zinc, titaniumand manganese as metals, the oxides being particularly preferred, suchas CaO, MgO, ZnO, TiO₂, MnO₂ and very particularly calcium oxide,magnesium oxide and zinc oxide. Calcium oxide is especially preferred.

It may also be possible, where appropriate, to use a mixture of variousinorganic compounds, for example a mixture of calcium oxide and calciumcarbonate.

An example which may be given of a metal hydroxide is magnesiumhydroxide, and an example which may be given of a metal carbonate iscalcium carbonate. It is also possible to use salts with various anions,for example magnesium aluminium hydroxycarbonates, known ashydrotalcites.

In addition to the macrocyclic compound, the hindered phenol, thephosphite or phosphonite, the metal soap and the metal oxide, metalhydroxide or metal carbonate, further stabilizers can be added to therecycled plastic. These further stabilizers are known in general termsto the person skilled in the art and are selected depending on thespecific requirements of the end product. In particular, lightstabilizers or antioxidants or further antioxidants can be added("Plastics Additives Handbook", Ed R. Gachter and H. Muller, HanserVerlag, 3rd Edn. 1990). It is also possible to add further additives,for example lubricants, mould-release agents, fillers or reinforcingsubstances, for example glass fibres, flameproofing agents orantistatics.

The following may be mentioned as being particularly suitable:

1. Antioxidants

1.1. Alkylated monophenols, for example2,6-di-tert-butyl-4-methylphenol, 2-butyl-4,6-dimethylphenol,2,6-di-tert-butyl-4-ethylphenol, 2,6-di-tert-butyl-4-n-butylphenol,2,6-di-tert-butyl-4-isobutylphenol, 2,6-dicyclopentyl-4-methylphenol,2-(α-methylcyclohexyl)-4,6-dimethylphenol,2,6-dioctadecyl-4-methylphenol, 2,4,6-tricyclohexylphenol,2,6-di-tert-butyl-4-methoxymethylphenol, 2,6-dinonyl-4-methylphenol,2,4dimethyl-6-(1'-methylundec-1'-yl)phenol,2,4-dimethyl-6-(1'-methylheptadec-1'-yl)phenol,2,4-dimethyl-6-(1'-methyltridec-1'-yl)phenol and mixtures thereof.

1.2. Alkylthiomethylphenols, for example2,4-dioctylthiomethyl-6-tert-butylphenol,2,4-dioctylthiomethyl-6-methylphenol,2,4-dioctylthiomethyl-6-ethylphenol,2,6-didodecylthiomethyl-4-nonylphenol.

1.3. Hydroquinones and alkylated hydroquinones, for example2,6-di-tert-butyl-4-methoxyphenol, 2,5-di-tert-butyl-hydroquinone,2,5-di-tert-amyl-hydroquinone, 2,6-diphenyl-4-octadecyloxyphenol,2,6-di-tert-butyl-hydroquinone, 2,5-di-tert-butyl-4-hydroxyanisole,3,5-di-tert-butyl-4-hydroxyanisole, 3,5-di-tert-butyl-4-hydroxyphenylstearate, bis(3,5-di-tert-butyl-4-hydroxyphenyl) adipate.

1.4. Chroman derivatives of the formula ##STR27## where R is --(CH₂)₃--CH(CH₃)--(CH₂)₃ --CH(CH₃)--(CH₂)₃ --CH--(CH₃)₂ or --CH₂ --CH₂--O--C(O)--Z, and Z is C₁ -C₁₈ alkyl, --CH₂ --CH₂ --S--C₁ -C₁₈ alkyl or##STR28## and R' and R" are hydrogen, methyl or tert-butyl, for exampleα-tocopherol, β-tocopherol, γ-tocopherol, δ-tocopherol and mixturesthereof (vitamin E).

1.5. Hydroxylated diphenyl thioethers, for example2,2'-thiobis(6-tert-butyl-4-methylphenol), 2,2'-thiobis(4-octylphenol),4,4'-thiobis(6-tert-butyl-3-methylphenol),4,4'-thiobis(6-tert-butyl-2-methylphenol),4,4'-thiobis(3,6di-sec-amylphenol),4,4'-bis(2,6-dimethyl-4-hydroxyphenyl)disulfide.

1.6. Alkylidenebisphenols, for example2,2'-methylene-bis(6-tert-butyl-4-methylphenol),2,2'-methylene-bis(6-tert-butyl-4-ethylphenol), 2,2'-methylene-bis4-methyl-6-(α-methylcyclohexyl)phenol!,2,2'-methylene-bis(4-methyl-6-cyclohexylphenol),2,2'-methylene-bis(6-nonyl-4-methylphenol),2,2'-methylene-bis(4,6-di-tert-butylphenol),2,2'-ethylidene-bis(4,6di-tert-butylphenol),2,2'-ethylidene-bis(6-tert-butyl-4-isobutylphenol), 2,2'-methylene-bis6(α-methylbenzyl)-4-nonylphenol!, 2,2'-methylene-bis6-(α,α-dimethylbenzyl)-4-nonylphenol!,4,4'-methylene-bis(2,6-di-tert-butylphenol),4,4'-methylene-bis(6-tert-butyl-2-methylphenol),1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,2,6-bis(3-tert-butyl-5-methyl-2-hydroxybenzyl)-4-methylphenol,1,1,3-tris(5-tert-butyl-4-hydroxy-2-methylphenyl)butane,1,1-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)-3-n-dodecylmercaptobutane,ethylene glycol bis 3,3-bis(3'-tert-butyl-4'-hydroxyphenyl) butyrate!,bis(3-tert-butyl-4-hydroxy-5-methylphenyl)dicyclopentadiene, bis2-(3'-tert-butyl-2'-hydroxy-5'-methylbenzyl)-6-tert-butyl-4-methyl-phenyl!terephthalate,1,1-bis(3,5-dimethyl-2-hydroxyphenyl)butane,2,2-bis(3,5-di-tert-butyl-4-hydroxyphenyl)propane,2,2-bis(5-tert-butyl-4-hydroxy-2-methylphenyl)-4-n-dodecylmercaptobutane,1,1,5,5-tetra(5-tert-butyl-4-hydroxy-2-methylphenyl)pentane.

1.7. O-, N- and S-benzyl compounds, for example3,5,3',5'-tetra-tert-butyl-4,4'-dihydroxydibenzyl ether, octadecyl4-hydroxy-3,5-dimethylbenzylmercaptoacetate,tris(3,5-di-tert-butyl-4-hydroxybenzyl)amine,bis(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) dithioterephthalate,bis(3,5-di-tert-butyl-4-hydroxybenzyl) sulfide, isooctyl3,5-di-tert-butyl-4-hydroxybenzylmercaptoacetate.

1.8. Hydroxybenzylated malonates, for example dioctadecyl2,2-bis(3,5-di-tert-butyl-2-hydroxybenzyl)malonate, dioctadecyl2-(3-tert-butyl-4-hydroxy-5-methylbenzyl)malonate,didodecylmercaptoethyl2,2-bis(3,5-di-tert-butyl-4-hydroxybenzyl)malonate, di4-(1,1,3,3-tetramethylbutyl)phenyl!2,2-bis(3,5-di-tert-butyl-4-hydroxybenzyl)malonate.

1.9. Hydroxybenzyl aromatic compounds, for example1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6-trimethylbenzene,1,4-bis(3,5-di-tert-butyl-4-hydroxybenzyl)-2,3,5,6-tetramethylbenzene,2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)phenol.

1.10. Triazine compounds, for example2,4-bisoctylmercapto-6-(3,5-di-tert-butyl-4-hydroxyanilino)-1,3,5-triazine,2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyanilino)-1,3,5-triazine,2-octylmercapto-4,6-bis(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,3,5-triazine,2,4,6-tris(3,5-di-tert-butyl-4-hydroxyphenoxy)-1,2,3-triazine,1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate,1,3,5-tris(4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) isocyanurate,2,4,6-tris(3,5-di-tert-butyl-4-hydroxyphenylethyl)-1,3,5-triazine,1,3,5-tris(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexahydro-1,3,5-triazine,1,3,5-tris(3,5-dicyclohexyl-4-hydroxybenzyl) isocyanurate.

1.11. Benzylphosphonates, for example dimethyl2,5-di-tert-butyl-4-hydroxybenzylphosphonate, diethyl3,5-di-tert-butyl-4-hydroxybenzylphosphonate, dioctadecyl3,5-di-tert-butyl-4-hydroxybenzylphosphonate, dioctadecyl5-tert-butyl-4-hydroxy-3-methylbenzylphosphonate, the calcium salt ofmonoethyl 3,5-di-tert-butyl-4-hydroxybenzyl phosphonate.

1.12. Acylaminophenols, for example 4-hydroxylauranilide,4-hydroxystearanilide, octylN-(3,5-di-tert-butyl-4-hydroxyphenyl)carbamate.

1.13. Esters of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid withmonohydric or polyhydric alcohols, for example with methanol, ethanol,octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol,1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethyleneglycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl)isocyanurate, N,N'-bis(hydroxyethyl)oxalamide, 3-thiaundecanol,3-thiapentadecanol, trimethylhexanediol, trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo- 2.2.2!-octane.

1.14. Esters of β-(5-tert-butyl-4-hydroxy-3-methylphenyl)propionic acidwith monohydric or polyhydric alcohols, for example with methanol,ethanol, octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethyleneglycol, 1,2-propanediol, neopentyl glycol, thiodiethylene glycol,diethylene glycol, triethylene glycol, pentaerythritol,tris(hydroxyethyl) isocyanurate, N,N'-bis(hydroxyethyl)oxalamide,3-thiaundecanol, 3-thiapentadecanol, trimethylhexanediol,trimethylopropane, 4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo-2.2.2!-octane .

1.15. Esters of β-(3,5-dicyclohexyl-4-hydroxyphenyl)propionic acid withmonohydric or polyhydric alcohols, for example with methanol, ethanol,octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol,1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethyleneglycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl)isocyanurate, N,N'-bis(hydroxyethyl)oxalamide, 3-thiaundecanol,3-thiapentadecanol, trimethylhexanediol, trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo- 2.2.2!-octane.

1.16. Esters of 3,5-di-tert-butyl-4-hydroxyphenylacetic acid withmonohydric or polyhydric alcohols, for example with methanol, ethanol,octanol, octadecanol, 1,6-hexanediol, 1,9-nonanediol, ethylene glycol,1,2-propanediol, neopentyl glycol, thiodiethylene glycol, diethyleneglycol, triethylene glycol, pentaerythritol, tris(hydroxyethyl)isocyanurate, N,N'-bis(hydroxyethyl)oxalamide, 3-thiaundecanol,3-thiapentadecanol, trimethylhexanediol, trimethylolpropane,4-hydroxymethyl-1-phospha-2,6,7-trioxabicyclo- 2.2.2!-octane.

1.17. Amides of β-(3,5-di-tert-butyl-4-hydroxyphenyl)proionic acid, forexampleN,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hexamethylenediamine,N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)trimethylenediamine,N,N'-bis(3,5-di-tert-butyl-4-hydroxyphenylpropionyl)hydrazine.

Furthermore, one or more additional light stabilizers or UV absorberscan be added, in accordance with the invention, to the plastic.Particularly suitable light stabilizers and UV absorbers for thispurpose are those from the series consisting of the benzophenones,benzotriazoles, oxanilides and linear, sterically hindered amines.Examples of such compounds are:

1. 2-(2'-Hydroxyphenyl)benzotriazoles, for example2-(2'-hydroxy-5'-methylphenyl)benzotriazole,2-(3',5'-di-tert-butyl-2'-hydroxyphenyl)benzotriazole,2-(5'-tert-butyl-2'-hydroxyphenyl)benzotriazole,2-(2'-hydroxy-5'-(1,1,3,3-tetramethylbutyl)phenyl)benzotriazole,2-(3',5'-di-tert-butyl-2'-hydroxyphenyl)-5-chlorobenzotriazole,2-(3'-tert-butyl-2'-hydroxy-5'-methylphenyl)-5-chlorobenzotriazole,2-(3'-sec-butyl-5'-tert-butyl-2'-hydroxyphenyl)benzotriazole,2-(2'-hydroxy-4'-octoxyphenyl)benzotriazole,2-(3',5'-di-tert-amyl-2'-hydroxyphenyl)benzotriazole,2-(3',5'-bis(α,α-dimethylbenzyl)-2'-hydroxyphenyl)benzotriazole, mixtureof2-(3'-tert-butyl-2'-hydroxy-5'-(2-octyloxycarbonylethyl)phenyl)-5-chlorobenzotriazole,2-(3'-tert-butyl-5'-2-(2-ethylhexyloxy)carbonylethyl!-2'-hydroxyphenyl)-5-chlorobenzotriazole,2-(3'-tert-butyl-2'-hydroxy-5'-(2-methoxycarbonylethyl)phenyl)-5-chlorobenzotriazole,2-(3'-tert-butyl-2'-hydroxy-5'-(2-methoxycarbonylethyl)phenyl)benzotriazole,2-(3'-tert-butyl-2'-hydroxy-5'-(2-octyloxycarbonylethyl)phenyl)benzotriazole,2-(3'-tert-butyl-5'-2-(2-ethylhexyloxy)carbonylethyl!-2'-hydroxyphenyl)benzotriazole,2-(3'-dodecyl-2'-hydroxy-5'-methylphenyl)benzotriazole, and2-(3'-tert-butyl-2'-hydroxy-5'-(2-isooctyloxycarbonylethyl)phenylbenzotriazole,2,2'-methylenebis 4-(1,1,3,3-tetramethylbutyl)-6-benzotriazol-2-ylphenol!; transesterification product of 2-3'-tert-butyl-5'-(2-methoxycarbonylethyl)-2'-hydroxyphenyl!benzotriazolewith polyethylene glycol 300; R--CH₂ CH₂ --COO(CH₂)₃ .brket close-st.₂where R=3'-tert-butyl-4'-hydroxy-5'-2H-benzotriazol-2-ylphenyl.

2. 2-Hydroxybenzophenones, for example the 4-hydroxy, 4-methoxy,4-octoxy, 4-decyloxy, 4-dodecyloxy, 4-benzyloxy, 4,2',4'-trihydroxy and2'-hydroxy-4,4'-dimethoxy derivatives.

3. Esters of unsubstituted or substituted benzoic acids, for example4-tert-butylphenyl salicylate, phenyl salicylate, octylphenylsalicylate, dibenzoylresorcinol, bis(4-tert-butylbenzoyl)resorcinol,benzoylresorcinol, 2,4-di-tert-butylphenyl3,5-di-tert-butyl-4-hydroxybenzoate, hexadecyl3,5-di-tert-butyl-4-hydroxybenzoate, octadecyl3,5-di-tert-butyl-4-hydroxybenzoate, 2-methyl-4,6-di-tert-butylphenyl3,5-di-tert-butyl-4-hydroxybenzoate.

4. Acrylates, for example ethyl and isooctylα-cyano-β,β-diphenylacrylate, methyl α-carbomethoxycinnamate, methyl andbutyl α-cyano-β-methyl-p-methoxycinnamate, methylα-carbomethoxy-p-methoxycinnamate andN-(β-carbomethoxy-β-cyanovinyl)-2-methylindoline.

5. Nickel compounds, for example nickel complexes of 2,2'-thiobis4-(1,1,3,3-tetramethylbutyl)phenol!, such as the 1:1 and 1:2 complexes,if desired with additional ligands, such as n-butylamine,triethanolamine or N-cyclohexyldiethanolamine, nickeldibutyldithiocarbamate, nickel salts of monoalkyl esters, such as themethyl or ethyl esters, of 4-hydroxy-3,5-di-tert-butylbenzylphosphonicacid, nickel complexes of ketoximes, such as of 2-hydroxy-4-methylphenylundecyl ketoxime, and nickel complexes of1-phenyl-4-lauroyl-5-hydroxypyrazole, if desired with additionalligands.

6. Linear sterically hindered amines, for examplebis(2,2,6,6-tetramethylpiperidyl) sebacate,bis(2,2,6,6-tetramethylpiperidyl) succinate,bis(1,2,2,6,6-pentamethylpiperidyl) sebacate,bis(1,2,2,6,6-pentamethylpiperidyl)n-butyl-3,5-di-tert-butyl-4-hydroxybenzylmalonate, the product of thecondensation of 1-hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxypiperidineand succinic acid, the product of the condensation ofN,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and4-tert-octylamino-2,6-dichloro-1,3,5-s-triazine,tris(2,2,6,6-tetramethyl-4-piperidyl) nitrilotriacetate,tetrakis(2,2,6,6-tetramethyl-4-piperidyl) 1,2,3,4-butanetetraoate,1,1'-(1,2-ethanediyl)bis-(3,3,5,5-tetramethylpiperazinone),4-benzoyl-2,2,6,6-tetramethylpiperidine,4-stearyloxy-2,2,6,6-tetramethylpiperidine,bis(1,2,2,6,6-pentamethylpiperidyl)2-n-butyl-2-(2-hydroxy-3,5-di-tert-butylbenzyl)malonate,3-n-octyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro 4.5!decane-2,4-dione,bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl)sebacate,bis(1-octyloxy-2,2,6,6-tetramethylpiperidyl) succinate, the product ofthe condensation ofN,N'-bis(2,2,6,6-tetramethyl-4-piperidyl)hexamethylenediamine and4morpholino-2,6-dichloro-1,3,5-triazine, the product of the condensationof2-chloro-4,6-di(4-n-butylamino-2,2,6,6-tetramethylpiperidyl)1,3,5-triazineand 1,2-bis(3-aminopropylamino)ethane, the product of the condensationof2-chloro-4,6-di(4-n-butylamino-1,2,2,6,6-pentamethylpiperidyl)-1,3,5-triazineand 1,2-bis(3-aminopropylamino)ethane,8-acetyl-3-dodecyl-7,7,9,9-tetramethyl-1,3,8-triazaspiro4.5!decane-2,4-dione,3-dodecyl-1-(2,2,6,6-tetramethyl-4-piperidyl)pyrrolidine-2,5-dione,3-dodecyl-1-(1,2,2,6,6-pentamethyl-4-piperidyl)pyrrolidine-2,5-dione,bis(1-octyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate.

7. Oxalamides, for example 4,4'-dioctyloxyoxanilide,2,2'-diethoxyoxanilide, 2,2'-dioctyloxy-5,5'-di-tert-butyloxanilide,2,2'-didodecyloxy-5,5'-di-tert-butyloxanilide,2-ethoxy-2'-ethyloxanilide, N,N'-bis(3-dimethylaminopropyl)oxalamide,2-ethoxy-5-tert-butyl-2'-ethyloxanilide and mixtures thereof with2-ethoxy-2'-ethyl-5,4'-di-tert-butyloxanilide, and mixtures of o- andp-methoxy- and of o- and p-ethoxy-disubstituted oxanilides.

8. 2-(2-Hydroxyphenyl)-1,3,5-triazines, for example2,4,6-tris(2-hydroxy-4-octyloxyphenyl)-1,3,5-triazine,2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-(2,4-dihydroxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2,4-bis(2-hydroxy-4-propoxyphenyl)-6-(2,4-dimethylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-octyloxyphenyl)-4,6-bis(4-methylphenyl)-1,3,5-triazine,2-(2-hydroxy-4-dodecyloxyphenyl)-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-2-hydroxy-4-(2-hydroxy-3-butoxypropoxy)phenyl!-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine,2-2-hydroxy-4-(2-hydroxy-3-octyloxypropoxy)phenyl!-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine.

The light stabilizers or UV absorbers are preferably added in an amountof from 0.01 to 2% by weight, in particular from 0.05 to 0.5% by weight,based on the plastic. The additional light stabilizer or UV absorber ispreferably a linear sterically hindered amine, a compound of thebenzotriazole type or a benzophenone.

The linear sterically hindered amine can be either alow-molecular-weight compound or an oligomeric or polymeric compound. Anexample of a preferred low-molecular-weight compound isbis(2,2,6,6-tetramethyl-4-piperidyl) sebacate. Examples which may bementioned of preferred oligomeric or polymeric compounds are poly{6-(1,1,3,3-tetramethylbutyl)amino!1,3,5-triazine-2,4-diyl!2-(2,2,6,6-tetramethyl-4-piperidyl)imino!hexamethylene4-(2,2,6,6-tetramethyl-4-piperidyl)imino!} (®Chimassorb 994),

poly-(N-β-hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxypiperidinylsuccinicacid ester (®Tinuvin 622) and 1,5,8,12-tetrakis 2,4-bisN-(1,2,2,6,6-pentamethyl-4-piperidyl)butylamino!-1,3,5-triazin-6-yl!-1,5,8,12-tetraazadodecane(®Chimassorb 119).

Particularly preferred compounds of the benzotriazole type are2-(3'-tert-butyl-2'-hydroxy-5'-methylphenyl)-5-chlorobenzotriazole,2-(3',5'-di-tert-butyl-2'-hydroxyphenyl)-5-chlorobenzotriazole and2-(3',5'-di-tert-butyl-2'-hydroxyphenyl)benzotriazole.

An example of a particularly preferred benzophenone is2-hydroxy-4-octoxybenzophenone.

If necessary, further conventional plastics additives can be added tothe recycled plastic, for example fillers, such as sawdust or mica,reinforcing materials, such as glass fibres, glass beads or mineralfibres, pigments, plasticizers, lubricants, flameproofing agents,antistatics or blowing agents. Such additives depend on the intended useof the recyclate.

The recycled plastic stabilized in accordance with the inventionpreferably additionally comprises a filler.

For the purposes of this invention, the term fillers is taken to mean,in particular, mineral fillers. Examples of mineral fillers arecarbonates (preferably calcium carbonates, such as chalk), silicates(preferably talc, kaolin, mica, wollastonite and silica), aluminiumtrihydrate, carbon black and titanium dioxide. Of the preferred fillerschalk, talc, kaolin, mica, wollastonite and silica, talc is veryparticularly preferred. It is possible to use either an individualfiller or a mixture of two or more fillers. Examples of such a mixtureof fillers are talc and carbon black or talc and titanium dioxide.

The filler can be present in an amount of 0.01-75% by weight, forexample 5-75% by weight or 10-40% by weight, based on the recycledplastic.

A preferred filler is carbon black, which is present in the recycledplastic in, in particular, an amount of 0.01-5% by weight.

In the case of plastic mixtures, it may also be advantageous to addcompatibilizers. The compatibilizers can be, for example, copolymers, inparticular block copolymers, of styrene and butadiene and, if desired,acrylonitrile. They can be copolymers of ethylene and propylene and mayalso contain a third monomer component, for example butadiene.

Chlorinated polyethylene or ethylene-vinyl acetate copolymers are alsosuitable as compatibilizers, naturally depending on the particularcomposition of the recyclate.

Further suitable compatibilizers contain, in particular, polar groups,for example maleic anhydride-styrene copolymers or graft polymerscontaining acrylic acid groups, maleic anhydride groups or glycidylgroups.

These polymeric compatibilizers are generally used in amounts of 2-20%by weight, based on the plastic mixture.

Further preferred embodiments of the invention are:

A) A stabilized recycled plastic comprising from 0.01 to 5% by weight,based on the plastic, of a mixture of compounds VII-A and VII-B, from0.01 to 2% by weight of at least one sterically hindered phenol, from0.01 to 2% by weight of at least one organic phosphite or phosphoniteand from 0.01 to 2% by weight of at least one metal soap.

B) A stabilized recycled plastic comprising from 0.01 to 5% by weight,based on the plastic, of a mixture of compounds VII-A and VII-B, from0.01 to 2% by weight of at least one sterically hindered phenol, from0.01 to 2% by weight of at least one organic phosphite or phosphoniteand from 0.01 to 2% by weight of at least one metal oxide and, ifdesired, from 0.01 to 2% by weight of at least one metal soap.

C) A stabilized recycled plastic comprising from 0.01 to 5% by weight,based on the plastic, of a mixture of compounds VII-A and VII-B, from0.01 to 2% by weight of at least one sterically hindered phenol, from0.01 to 2% by weight of at least one organic phosphite or phosphoniteand from 0.01 to 2% by weight of at least one linear sterically hinderedamine.

D) A stabilized recycled plastic comprising from 0.01 to 5% by weight,based on the plastic, of a mixture of compounds VII-A and VII-B, from0.01 to 2% by weight of at least one sterically hindered phenol, from0.01 to 2% by weight of at least one organic phosphite or phosphoniteand from 0.01 to 2% by weight of at least one benzotriazole.

Further particularly preferred embodiments of the invention are thefollowing:

I) A stabilized recycled plastic comprising from 0.01 to 5% by weight,based on the plastic, of a mixture of compounds VII-A and VII-B and from0.01 to 2% by weight ofpoly(N-β-hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxypiperidinylsuccinicacid ester).

II) A stabilized recycled plastic comprising from 0.01 to 5% by weight,based on the plastic, of a mixture of compounds VII-A and VII-B and from0.01 to 2% by weight of2-(3'-tert-butyl-2'-hydroxy-5'-methylphenyl)-5-chlorobenzotriazole,2-(3',5'-di-tert-butyl-2'-hydroxyphenyl)-5-chlorobenzotriazole or2-(3',5'-di-tert-butyl-2'-hydroxyphenyl)benzotriazole.

III) A stabilized recycled plastic comprising from 0.01 to 5% by weight,based on the plastic, of a mixture of compounds VII-A and VII-B, from0.01 to 2% by weight of the pentaerythrityl ester ofβ-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, from 0.01 to 2% byweight of tris(2,4-di-tert-butylphenyl) phosphite and from 0.01 to 2% byweight of calcium stearate.

IV) A stabilized recycled plastic comprising from 0.01 to 5% by weight,based on the plastic, of a mixture of compounds VII-A and VII-B, from0.01 to 2% by weight of the pentaerythrityl ester ofβ-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, from 0.01 to 2% byweight of tris(2,4-di-tert-butylphenyl) phosphite and from 0.01 to 2% byweight of calcium oxide.

V) A stabilized recycled plastic comprising from 0.01 to 5% by weight,based on the plastic, of a mixture of compounds VII-A and VII-B, from0.01 to 2% by weight of the pentaerythrityl ester ofβ-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, from 0.01 to 2% byweight of tris(2,4-di-tert-butylphenyl) phosphite and from 0.01 to 2% byweight ofpoly(N-β-hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxypiperidinylsuccinicacid ester).

VI) A stabilized recycled plastic comprising from 0.01 to 5% by weight,based on the plastic, of a mixture of compounds VII-A and VII-B, from0.01 to 2% by weight of the pentaerythrityl ester ofβ-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, from 0.01 to 2% byweight of tris(2,4-di-tert-butylphenyl) phosphite and from 0.01 to 2% byweight of poly{ 6-(1,1,3,3-tetramethylbutyl)amino!-1,3,5-triazin-2,4-diyl!2-(2,2,6,6-tetramethyl-4-piperidyl)imino!hexamethylene4-(2,2,6,6-tetramethyl-4-piperidyl)imino!}.

VII) A stabilized recycled plastic comprising from 0.01 to 5% by weight,based on the plastic, of a mixture of compounds VII-A and VII-B, from0.01 to 2% by weight of the pentaerythrityl ester ofβ-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid, from 0.01 to 2% byweight of tris(2,4-di-tert-butylphenyl) phosphite and from 0.01 to 2% byweight of2-(3'-tert-butyl-2'-hydroxy-5'-methylphenyl)-5-chlorobenzotriazole,2-(3',5'-di-tert-butyl-2'-hydroxyphenyl)-5-chlorobenzotriazole or2-(3',5'-di-tert-butyl-2'-hydroxyphenyl)benzotriazole.

The invention also relates to a stabilizer mixture comprising from 0.01to 5 parts of a mixture of compounds VII-A and VII-B in a ratio of from10:1 to 1:10, from 0.01 to 2 parts of at least one sterically hinderedphenol, from 0.01 to 2 parts of at least one organic phosphite orphosphonite and from 0.01 to 2 parts of at least one metal soap, metaloxide, linear sterically hindered amine or benzotriazole.

The invention also relates to a stabilizer mixture comprising from 0.01to 5 parts of a mixture of compounds VII-A and VII-B in a ratio of from10:1 to 1:10 and from 0.01 to 2 parts of at least one benzotriazole orbenzophenone, and, if desired, from 0.01 to 2 parts of a linearsterically hindered amine.

The invention furthermore relates to a process for the stabilization ofrecycled plastics, which comprises adding to the plastic or plasticmixture from 0.01 to 5% by weight, based on the plastic, of at least onemacrocyclic compound containing a radical of the formula ##STR29## inthe macrocycle or in a side group of the macrocycle, where themacrocycle comprises at least 8 atoms and in which the substituents R,independently of one another, are methyl, ethyl or propyl, butpreferably methyl, or two radicals R on the same carbon atom togetherare alternatively a pentamethylene radical, and a is the number 0, 1 or2, preferably 0.

The invention furthermore relates to the use of at least one macrocycliccompound containing a radical of the formula ##STR30## in the macrocycleor in a side group of the macrocycle, where the macrocycle comprises atleast 8 atoms and in which the substituents R, independently of oneanother, are methyl, ethyl or propyl, but preferably methyl, or tworadicals R on the same carbon atom together are alternatively apentamethylene radical, and a is the number 0, 1 or 2, preferably 0, forstabilizing recycled plastics, for example recycled plastics containingcarbon black.

The preferences described in greater detail above for the stabilizedrecycled plastics and plastic mixtures apply analogously to the novelprocess and use.

The novel stabilizer or mixtures comprising same and, if desired, theadditives mentioned can be employed in compact, extruded form or on asupport material, or alternatively can be added directly to therecyclate as a mixture or in the form of powders. In this case, thestabilizers can be added individually or as a mixture or alternativelyin the form of a masterbatch.

The recyclate stabilized in accordance with the present invention can beconverted into the desired shape by known methods. Such methods are, forexample, grinding, calendering, extrusion, injection moulding,sintering, spinning and extrusion blow moulding.

The recyclates stabilized in this way can be used for a wide variety ofpurposes, for example for pipes, profiles, sheets, cable insulation,sports equipment, garden furniture, films, construction parts,automobile and machine parts and receptacles of all types, for examplebottles, drums or containers.

The recyclate can also be mixed with fresh plastics or employed togetherwith fresh plastics, for example in a coextrusion process.

The examples below illustrate the invention in greater detail. In theseexamples, as in the remainder of the description, parts and percentagesare by weight, and ##STR31## denotes tert-butyl, unless specifiedotherwise.

EXAMPLES 1 AND 2

48.5 g of HIPS/PS recyclate (high impact polystyrene:polystyrene 60:40)are compounded for 10 minutes under a nitrogen atmosphere in a BrabenderW50 mixer (46 rpm) heated to 200° C. The additives (Table 1) areintroduced into the mixer right at the beginning together with theplastic mixture. After 10 minutes, the mixing is terminated, and thepolymer composition is removed from the mixer and pre-pressed at 30° C.for 1 minute at approx. 50 kN.

From this compact, sheets with a thickness of 2 mm are produced at 200°C./50 kN. Dumbbell-shaped test specimens are stamped therefrom. Thesespecimens are subjected to oven ageing at 80° C. until they becomebrittle (flexural test).

The comparative example is carried out analogously.

                  TABLE 1                                                         ______________________________________                                                                 Time before                                                                   embrittlement                                               %        Additive  d!                                                  ______________________________________                                        Comp. 1  --         none     15                                               Ex. 1    0.20       Ch. 966  19                                               Ex. 2    0.40       Ch. 966  21                                               ______________________________________                                    

The samples stabilized in accordance with the invention exhibit improveddurability.

EXAMPLES 3 AND 4

36.6 g of HDPE recyclate are compounded for 10 minutes under a nitrogenatmosphere in a Brabender W50 mixer (46 rpm) heated to 200° C. Theadditives (Table 2) are introduced into the mixer right at the beginningtogether with the plastic. After 10 minutes, the mixing is terminated,and the polymer composition is removed from the mixer and pre-pressed at30° C. for 1 minute at approx. 50 kN.

From this compact, sheets with a thickness of 2 mm are produced at 200°C./50 kN. Dumbbell-shaped test specimens are stamped therefrom. Thesespecimens are subjected to oven ageing at 120° C. until they becomebrittle (flexural test).

The comparative example is carried out analogously.

                  TABLE 2                                                         ______________________________________                                                                 Time before                                                                   embrittlement                                               %        Additive  d!                                                  ______________________________________                                        Comp. 1  --         none      67                                              Ex. 1    0.20       Ch. 966  106                                              Ex. 2    0.40       Ch. 966  138                                              ______________________________________                                    

The samples stabilized in accordance with the invention exhibit improveddurability.

EXAMPLE 5

The experiments are carried out with a recycled plastic mixture havingthe composition 80% of PO, 15% of PS, 2% of PET and 3% of PVC.

39 g of the plastic mixture are compounded for 10 minutes in a BrabenderW50 mixer (46 rpm) heated to 200° C. The additives (Table 3) areintroduced into the mixer right at the beginning together with theplastic mixture. After 10 minutes, the mixing is terminated, and thepolymer composition is removed from the mixer and pre-pressed at 30° C.for 1 minute at approx. 50 kN.

From this compact, sheets with a thickness of 2 mm are produced at 200°C./50 kN. Dumbbell-shaped test specimens are stamped therefrom. Thesespecimens are subjected to oven ageing at 110° C. until they becomebrittle (flexural test).

The comparative examples are carried out analogously.

                  TABLE 3                                                         ______________________________________                                                                    Time before                                                                   embrittlement                                            %         Additive    d!                                               ______________________________________                                        Comp. 3  --          none       4                                             Comp. 4  0.04/0.04/0.12                                                                            AO-1/P-1/M-1                                                                             30                                            Ex. 5    0.04/0.04/0.12/                                                                           AO-1/P-1/M-1/                                                                            50                                                     0.20        Ch.966                                                   ______________________________________                                    

The sample stabilized in accordance with the invention exhibits improveddurability.

EXAMPLES 6-12

HDPE recyclate is premixed with the additives (Tables 4 and 5) and thenhomogenized at a maximum of 240° C. and 100 rpm with the aid of atwin-screw compounder (ZSK 25). Dumbbell-shaped test specimens are thenproduced by injection moulding.

These specimens are subjected to oven ageing at 120° C. After 2000hours, the residual impact strength is determined (DIN 53 448) (Table4).

The comparative examples are carried out analogously.

                  TABLE 4                                                         ______________________________________                                                          Residual impact strength  %!                                         Additive   Start      2000 h                                         ______________________________________                                        Comp.5                                                                              --       none         100      9                                        Ex. 6 0.20     Ch. 966      100      84                                       Ex. 7 0.2/0.12/                                                                              Ch. 966/M-1/AO-2/                                                                          100      96                                             0.04/0.04                                                                              P-1                                                            ______________________________________                                    

The samples stabilized in accordance with the invention exhibit betterresidual impact strength than the comparative example.

The dumbbell-shaped test specimens described above are subjected in afurther test to artificial weathering in a Weather-O-Meter WOM Ci 65 ata BPT (black panel temperature) of 63° C. and a relative humidity RH of60%. After weathering for the indicated number of hours, the impactstrength is determined (DIN 53 448) (Table 5).

                  TABLE 5                                                         ______________________________________                                                        Impact strength  kJ/m.sup.2 !                                 %          Additive   Start  2000 h                                                                              5000 h                                                                              7000 h                               ______________________________________                                        Comp.6                                                                              --       none       344  270   252   217                                Ex. 8 0.20     Ch. 966    370  369   343   330                                Ex. 9 0.2/0.12/                                                                              Ch. 966/M-1/                                                                             361  355   343   344                                      0.04/0.04                                                                              AO-2/P-1                                                       Ex. 10                                                                              0.1/0.1  Ch. 966/T.622                                                                            355  363   344   369                                Ex. 11                                                                              0.2/0.2  Ch. 966/T.770                                                                            376  376   377   359                                Ex. 12                                                                              0.2/0.2  Ch. 966/T.326                                                                            366  357   344   356                                ______________________________________                                    

The samples stabilized in accordance with the invention exhibit betterimpact strength than the comparative example.

EXAMPLES 13

A recycled plastic mixture (64% of HDPE/22% of LDPE and 14% of PP) ispremixed with the additives (Table 6) and then homogenized at a maximumof 240° C. and 100 rpm with the aid of a twin-screw compounder (ZSK 25).Dumbbell-shaped test specimens are then produced by injection moulding.

These specimens are subjected to oven ageing at 120° C. After 3000hours, the impact strength is determined (DIN 53 448) (Table 6).

The comparative examples are carried out analogously.

                  TABLE 6                                                         ______________________________________                                                               Residual impact                                                               strength  %!                                           %            Additive        500 h   3000 h                                   ______________________________________                                        Comp.7                                                                              0.8        Carbon black    100   6                                      Ex. 13                                                                              0.8/0.40/0.02/                                                                           Carbon black/Ch.966/M-1/                                                                      100   70                                           0.08/0.05/0.05                                                                           M-2/AO-2/P-1                                                 ______________________________________                                    

The samples stabilized in accordance with the invention exhibit betterresidual impact strength than the comparative examples.

EXAMPLES 14 AND 15

A recycled plastic mixture (64% of HDPE/22% of LDPE and 14% of PP) ispremixed with the additives (Table 7) and then homogenized at a maximumof 240° C. and 100 rpm with the aid of a twin-screw compounder (ZSK 25).Dumbbell-shaped test specimens are then produced by injection moulding.

These specimens are subjected to artificial weathering in aWeather-O-Meter WOM Ci 65 at a BPT of 63° C. and a relative humidity RHof 60%. After 2000 hours, the residual impact strength is determined(DIN 53 448) (Table 7).

The comparative examples are carried out analogously.

                  TABLE 7                                                         ______________________________________                                                               Residual impact                                                               strength  %!                                           %            Additive        0 h     2000 h                                   ______________________________________                                        Comp. 0.2        Carbon black    100   79                                     Ex. 14                                                                              0.8/0.40/0.02/                                                                           Carbon black/Ch.966/M-1/                                                                      100   92                                           0.08/0.05/0.05                                                                           M-2/AO-2/P-1                                                 Ex. 15                                                                              0.8/0.40/0.02/                                                                           Carbon black/Ch. 966/M-1/                                                                     100   103                                          0.08/0.05/0.05                                                                           M-2/AO-2/P-1                                                 ______________________________________                                    

The samples stabilized in accordance with the invention exhibit betterresidual impact strength than the comparative example.

EXAMPLES 16-19

A recycled plastic mixture (95% of PE/5% of PP) is premixed with theadditives (Table 8) and then homogenized at a maximum of 240° C. and 30rpm with the aid of a single-screw compounder. Dumbbell-shaped testspecimens are then produced by injection moulding.

These specimens are additionally subjected to artificial weathering in aWeather-O-Meter Atlas Ci 65 A at a BPT of 63° C. and a relative humidityRH of 60%. After weathering for the stated number of hours, the residualimpact strength is determined (DIN 53 448) (Table 8).

The comparative examples are carried out analogously.

                                      TABLE 8                                     __________________________________________________________________________                       Residual impact strength  %!                               %           Additive                                                                             Start                                                                             1000 h                                                                            2000 h                                                                            5000 h                                                                            6500 h                                     __________________________________________________________________________    Comp. 9                                                                            --     No additive                                                                          100 73  55  55  35                                         Ex. 16                                                                             0.05/0.05/0.10/                                                                      AO-2/P-1/M-1                                                                         100 88  81  73  77                                              0.20   Ch. 966                                                           Ex. 17                                                                             0.05/0.05/0.10/                                                                      AO-2/P-1/M-1                                                                         100 90  75  77  79                                              0.10/0.10                                                                            Ch. 966/T.622                                                     Ex. 18                                                                             0.05/0.05/0.10/                                                                      AO-2/P-1/M-1                                                                         100 88  76  82  85                                              0.10/0.10                                                                            Ch. 966/T.770                                                     Ex. 19                                                                             0.40/0.30/0.30                                                                       M-1/Ch. 966/                                                                         100 93  72  84  81                                                     T.326                                                             __________________________________________________________________________

The samples stabilized in accordance with the invention exhibit betterresidual impact strength than the comparative example.

Compounds and abbreviations used in the examples:

Ch. 966: Mixture of the compounds ##STR32## where L₁ is ##STR33## R is--CH₃, R₁ is H and a=0 in a ratio of 7:3.

AO-1: Octadecyl ester of β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionicacid

AO-2: Pentaerythrityl ester ofβ-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid

M-1: Calcium stearate

M-2: Calcium oxide

P-1: Tris(2,4-di-tert-butylphenyl) phosphite

T.622:Poly(N-β-hydroxyethyl-2,2,6,6-tetramethyl-4-hydroxypiperidinylsuccinicester)

T.770: Bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate

T.326:2-(3'-tert-Butyl-2'-hydroxy-5'-methylphenyl)-5-chlorobenzotriazole

HDPE: High-density polyethylene

LDPE: Low-density polyethylene

PO: Polyolefin

PE: Polyethylene

PP: Polypropylene

PS: Polystyrene

PET: Polyethylene terephthalate

PVC: Polyvinyl chloride

What is claimed is:
 1. A stabilized recycled plastic, which can beobtained from domestic, commercial and industrial waste or valuablematerial collections, comprising from 0.01 to 5% by weight, based on theplastic, of at least one macrocyclic compound of the formula ##STR34##where L₁ is the radical ##STR35## and A₇ is --NR₄ R₆ ;R is methyl; R₁ ishydrogen, oxygen, hydroxyl, C₁ -C₁₂ alkyl, C₃ -C₈ alkenyl, phenyl-C₁ -C₆alkyl, C₁ -C₁₈ alkoxy, C₃ -C₅ alkenoyl or C₁ -C₁₈ alkanoyloxy; R₄ ishydrogen, C₁ -C₁₂ alkyl or, together with R₆, --(CH₂)₂ --O--(CH₂)₂ --;R₅ is C₁ -C₁₈ alkyl; R₆ is C₁ -C₁₈ alkyl, C₃ -C₁₈ alkenyl, C₅ -C₁₈cycloalkyl, substituted or unsubstituted phenyl, substitute orunsubstituted phenyl-C₁ -C₆ alkyl, --CH₂ --C(═O)--O--R₅ or, togetherwith R₄, --(CH₂)₂ --O--(CH₂)₂ --; a is the number 0, 1 or 2; n₄ is anumber from 1 to 12; and t₃ is a number from 1 to
 4. 2. A stabilizedrecycled plastic according to claim 1, wherein from 0.01 to 2% by weightof at least one sterically hindered phenol and/or from 0.01 to 2% byweight of at least one organic phosphite or phosphonite are additionallyadded to the recycled plastic.
 3. A stabilized recycled plasticaccording to claim 1, wherein at least one sterically hindered phenoland at least one organic phosphite or phosphonite in a weight ratio offrom 20:1 to 1:20 are additionally added to the recycled plastic.
 4. Astabilized recycled plastic according to claim 1, wherein at least onemetal soap or inorganic compound from the series consisting of metaloxides, metal hydroxides and metal carbonates is additionally added tothe recycled plastic.
 5. A stabilized recycled plastic according toclaim 1, additionally comprising a filler.
 6. A stabilized recycledplastic according to claim 1, additionally comprising carbon black.
 7. Astabilized recycled plastic according to claim 1, wherein at least onecompatibilizer is additionally added to the recycled plastic.
 8. Astabilized recycled plastic according to claim 1, wherein a lightstabilizer or UV absorber from the series consisting of thebenzophenones, benzotriazoles, oxanilides and linear sterically hinderedamines is additionally added to the recycled plastic.
 9. A stabilizedrecycled plastic according to claim 1, additionally comprising a linearsterically hindered amine.
 10. A stabilizer mixture comprising from 0.01to 5 parts of a mixture of compounds VII-A and VII-B ##STR36## where L₁is ##STR37## R is --CH₃, R₁ is H, and a is 0, in a ratio of from 10:1 to1:10, from 0.01 to 2 parts of at least one sterically hindered phenol,from 0.01 to 2 parts of at least one organic phosphite or phosphoniteand from 0.01 to 2 parts of at least one metal soap, metal oxide, linearsterically hindered amine or benzotriazole.
 11. A stabilizer mixturecomprising from 0.01 to 5 parts of a mixture of compounds VII-A andVII-B ##STR38## where L₁ is ##STR39## R is --CH₃, R₁ is H, and a is 0,in a ratio of from 10:1 to 1:10, and from 0.01 to 2 parts of at leastone benzotriazole or benzophenone.
 12. A stabilized recycled plasticaccording to claim 1, comprising from 0.01 to 5% by weight, based on theplastic, of a mixture of compounds VII-A and VII-B ##STR40## where L₁ is##STR41## R is --CH₃, R₁ is H, and a is 0, in a ratio of from 10:1 to1:10.
 13. A process for the stabilization of recycled plastics, whichcomprises adding to the plastic or plastic mixture from 0.01 to 5% byweight, based on the plastic, of at least one macrocyclic compound ofthe formula ##STR42## where L₁ is the radical ##STR43## and A₇ is --NR₄R₆ ;R is methyl; R₁ is hydrogen, oxygen, hydroxyl, C₁ -C₁₂ alkyl, C₃ -C₈alkenyl, phenyl--C₁ -C₆ alkyl, C₁ -C₁₈ alkoxy, C₃ -C₅ alkenoyl or C₁-C₁₈ alkanoyloxy; R₄ is hydrogen, C₁ -C₁₂ alkyl or, together with R₆,--(CH₂)₂ --O--(CH₂)₂ --; R₅ is C₁ -C₁₈ alkyl; R₆ is C₁ -C₁₈ alkyl, C₃-C₁₈ alkenyl, C₅ -C₁₈ cycloalkyl, substituted or unsubstituted phenyl,substituted or unsubstituted phenyl--C₁ -C₆ alkyl, --CH₂ --C(═O)--O--R₅or, together with R₄, --(CH₂)₂ --O--(CH₂)₂ --; a is the number 0, 1 or2; n₄ is a number from 1 to 12; and t₃ is a number from 1 to
 4. 14. Aprocess according to claim 13 for the stabilization of recycledplastics, which comprises adding to the plastic or plastic mixture from0.01 to 5% by weight, based on the plastic, of a mixture of compoundsVII-A and VII-B ##STR44## where L₁ is ##STR45## R is --CH₃, R₁ is H, anda is 0, in a ratio of from 10:1 to 1:10.